I don't think that's nearly as clear as it sounds. The things which are Caesar's really isn't specific as to what it's entailing. And here's what it is entailing: Caesar owns your land, and you then owe your taxes basically at his whim. But no matter how powerful, his law is subservient to God's. God owns your life, and Caesar does not. Does that make sense? You do owe to your ruler what they wish of you, save for denying God.

He even explains in detail in a few spots ... basically the concept to me seems to be that if life "kinda works", it's well enough and not of your concern. Your battle is not with powers or principalities, but with corruption in high spiritual places. Your own morals, and your own guilt, and your own struggle, and your own fights. Not the annoyance with an overbearing government. Could that be said to encourage being a slave? Kinda, yeah. Trust me, and trust Jesus, you don't want the power you think you do.